Field of the Invention
The present invention relates to a manual opening/closing valve configured such that a valve element is moved into contact with a valve seat by rotation of a manual handle, thereby cutting off communication between an input port and an output port.
Related Art
In a production process of semiconductors, a manual opening/closing valve to allow an operator to reliably cut off gas supply by manual operation is widely used for equipment or facilities of supplying process gas, etc. For example, the manual opening/closing valve is used when it is necessary to stop supplying process gas during normal operation or to avoid flowing process gas during maintenance in which pipes and others are removed or disconnected from the equipment.
Patent Document 1 discloses a fluid control device having a mechanism of moving a valve element in a direction toward a valve seat by a screw structure when a manual handle is rotated and a structure of urging an urging spring in a direction to bring the valve element into contact with the valve seat.
The process gas to be used in the above device is highly corrosive. Thus, the valve seat is made of resin such as trifluoroethylene, etc. In order to prevent large deformation of the valve seat even when an operator rotates the manual handle too much, the above device is configured to make the valve element contact with the valve seat by only the force of the urging spring.
Patent Document 2 discloses that a padlock is attached to a manual handle to lock this handle in order to keep the manual opening/closing valve in a closed state during maintenance for the safety of the operator.